#define _CRT_SECURE_NO_WARNINGS
#include <iostream>

using namespace std;

namespace Math {
	int add(int x, int y) {
		return x + y;
	}
	int sub(int x, int y) {
		return x - y;
	}
}
using Math::add;
int main() {
	int x = 1;
	int y = 2;
	cout << add(x, y) << endl;
	cout << Math::sub(x, y) << endl;
	return 0;
}